aspnet postgresql connection setting

Dear Support Team,
Our website is produced by using aspnet + mssql, and then we would like to move database from mssql to postgresql. But about the database connection setting in web.config, we are not sure how to modify the setting as listed as below:
<add key="CconString" value="Server='7a0642076\SQLEXPRESS';uid='sa';pwd='water';database='DB14017'"/>
<add key="VBconString" value="Server=7a0642076\SQLEXPRESS;uid=sa;pwd=water;database=DB14017"/>
<add key="SMTPServer" value="mail.ehosting.com.tw"/>
<add key="SMTPSend" value="zenki(at)creatop(dot)com(dot)tw<mailto:zenki(at)creatop(dot)com(dot)tw>"/>
<add key="SystemName" value="SmartAdmin"/>
<add key="AbsPath" value="/"/>
<add key="TrackSaveTime" value="/3/"/>
<add key="EditUploadPath" value="\\nas2\webhost\17\14017\upfiles\EditUpload\"/>
<add key="UploadPath" value="\\nas2\webhost\17\14017\upfiles\ADUpload\"/>
<add key="CopyRight" value="http://www.creatop.com.tw/"/>
<add key="sKey" value="qJzGEh6hESZDVJeCnFPGuxz3"/>
<add key="sIV" value="qcD="/>
<add key="MainWeb" value="http://www.fengtay.com/"/>

Would it be possible to guidance the information which how to modify postgresql in web.config? Thanks a lot.
Best Regards, Anderson Hsu